Crowd shovel excavators



Dec. 13, 1966 N. BROCKLEBANK 3,

CROWD SHOVEL EXCAVATORS Filed Oct. 4, 1965 2 Sheets-Sheet l Inventor NORMAN EKQcKLEBANK +mus A tlorneys Dec. 13, 1966 N. BROCKLEBANK CROWD SHOVEL EXGAVATORS 2 Sheets-Sheet 2 Filed Oct. 4, 1965 NdRMAN BROCK LEBANK y cum/Ln,

United States Patent 3,291,328 CROWD SHOVEL EXCAVATORS Norman Brocklebank, Beverley, England, assignor to Priestman Brothers Limited, Yorkshire, England, a British company Filed Oct. 4, 1965, Ser. No. 492,469 Claims priority, application Great Britain, Oct. 9, 1964, 41,339/64 1 Claim. (Cl. 214138) This invention relates to crowd shovel excavators of the kind in which a dipper handle carrying a digging bucket at one end is carried from a boom of the machine in such a way that the dipper handle extends downwards from the boom and can move bodily with an appreciable component of movement parallel to its length relatively and transversely to and through the boom to perform a crowding action and can swing forwards and backwards in a vertical plane relatively to the boom so that the bucket performs a forward and upward scooping action on a changing radius of curvature.

With previous crowd shovel excavators of this kind, the dipper handle has usually been mounted on the boom by means of a saddle through which the dipper handle slides longitudinally for crowding and which is pivotally mounted about a horizontal axis on the boom so that the dipper handle and bucket can perform the scooping movement. These two movements have been controlled by ropes which extend from winches on the machine along the boom. Even though the rope which controls the scooping movement has passed to the bucket over a sheave on the boom well beyond the position of the saddle, we find that this construction has a severe disadvantage that when a cut is started at or below ground level, the cutting speed is too high owing to the unfavourable angle of rope pull.

In accordance with the present invention the dipper handle of a crowd shovel excavator of the kind described is pivotally mounted on a crowd arm which is pivotally mounted on the boom of the machine, the dipper handle being rockable relatively to the crowd arm by means of a fluid operated ram to provide the scooping action, and the crowd arm being rockable relatively to the boom by means of a second fluid operated ram to provide the crowding action,

With this extremely simple arrangement the speed and force with which the bucket is moved during digging can be readily controlled over its full range of movement.

Although the dipper handle does not slide longitudinally relatively to the boom, as in conventional crowd shovel excavators, the dipper handle can still be moved substantially parallel to its length bodily relatively and transversely to and through the boom upon movement of the crowd arm and this is all that is necessary to provide a satisfactory crowding action.

Preferably, the crowd arm is pivotally mounted at one end on the outer end of the boom and extends below and back along the boom to a pivotal connection at its other end to between the ends of the dipper handle, the first ram interconnecting the crowd arm and the end of the dipper handle remote from the bucket. The digging bucket is rigidly mounted facing forwards at the lower end of the dipper handle and the upper end of the dipper handle, which is connected by a ram to the crowd arm, is free to pass through the boom when the crowd arm is rocked so that the dipper handle is retracted. The digging bucket can alternatively be rockably mounted and controlled by a hydraulic ram for forward discharge or for varying the digging angle.

One example of a crowd shovel excavator constructed in accordance with the present invention is illustrated in the accompanying drawings, in which:

FIGURE 1 is a perspective view of the excavator; and,

FIGURE 2 is a side elevation of the excavator.

The excavator has a base machine consisting of a superstructure 3 mounted on a track laying chassis 4 through a turntable 5. A boom 6 consisting of two box sections extending side by side and connected together at their upper ends by a cross pin 7, is pivotally mounted about a transverse axis 8 on the superstructure 3 and is lutfed by means of conventional rope pulls 9 from a hoist drum on the superstructure. The boom angle however is intended to remain fixed during a digging cut.

One end of a substantially L shaped crowd arm 10 consisting of two component plates arranged face to face is pivotally mounted on the pin 7 at the outer end of the boom so that the arm 10, in a neutral position, extends downwards and back along beneath the boom 6. At its other end, the crowd arm 10 is pivotally mounted by means of a transverse pin 11 near to the mid-point of a dipper handle 12 to the lower end of which a digging bucket 13 is rigidly mounted but detachable.

A pair of double acting hydraulic crowding rams 14 extend side by side from transverse pivotal connections 15 one to each box section near the bottom of the boom 6 to transverse pivotal connections 16 adjacent to the outer corner of the angle of the L of the crowd arm 10. A single double acting hydraulic scoop ram 17 is connected by a transverse pivotal connection 18 to the upper free end of the dipper handle and to the crowd arm 10 by means of another transverse pivotal connection 19 adjacent to the top of the boom.

Retr'action of the crowding rams 14 causes the crowd arm 10 to rock transversely to the boom in a vertical plane towards or away from the underside of the boom, during which movement the upper end of the dipper handle 12 passes between the box sections of the boom as shown in chain dotted lines in FIGURE 2, to provide a crowding action. During this action, the angle between the length of the dipper handle 12 and its bodily direction of movement will depend upon the relative orientation of the crowd arm 10 and the boom 6, and the dipper handle 12 and crowd arm 10, but this angle will remain small through an appreciable range of movement of the bucket. Extension of the scooping ram 17 causes the dipper handle 12 to rock relatively to the crowd arm 10 so that the bucket carries out an upwards scooping action.

In practice, the crowding ram 14 and the scooping ram 17 may be operated simultaneously so that the machine performs a crowding and scooping action at the same time, or they may be operated independently as the occasion demands.

The hydraulic circuits for the crowding and scooping rams are controlled by separate levers or by means of a single joy stick which is connected to control valves for both circuits. In this way movement of the single joy stick or the separate levers can provide a range of operation between no movement of the crowding rams and maximum movement of the scooping ram to maximum movement of the crowding rams and no movement of the scooping ram.

I claim:

A crowd shovel comprising a base machine, a boom pivotally mounted on said base machine, means adapted to luif said boom relatively to said base machine, a crowd arm having first and second ends, means pivotally mounting said first end of said crowd arm on the outer end of said boom for rocking movement in a vertical plane thereabout, a dipper handle having first and second ends, means pivotally mounting said dipper handle intermediate its said ends on said second end of saidcrowd arm for swinging movement thereabout, a digging bucket mounted on said first end of said dipper handle facing away from said base machine, first fluid operated ram means interconnecting said crowd arm and said second end of said dipper handle whereby upon operation thereof said dipper handle and bucket are caused to perform a forward and upward scooping action, second fluid operated ram means interconnecting said boom and said crowd arm intermediate said first and second ends of said crowd arm whereby said crowd arm is swingable in a vertical plane between a position in which said crowd arm extends backwards along and beneath said boom and said second end of said dipper handle ex- References Cited by the Examiner UNITED STATES PATENTS 7/1930 Norris 214138 X 5/1966 Guinot 214138 HUGA O. SCHULZ, Primary Examiner. 

